Mesoscale Discussion 2047

Issued

Dec 18, 2021, 12:50 PM CST (18:50 UTC)

Expired

Dec 18, 2021, 2:45 PM CST

In force

115 min

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch unlikely

Chance of a watch

20%

Counties Acadia Parish, LA, Allen Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Evangeline Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Rapides Parish, LA, Saint Landry Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Jefferson County, TX, Newton County, TX, Orange County, TX

The Lake Charles radar (KLCH), 10 km from the middle of the area, began a volume at 18:53 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

611 
ACUS11 KWNS 181851
SWOMCD
SPC MCD 181850 
LAZ000-TXZ000-182045-

Mesoscale Discussion 2047
NWS Storm Prediction Center Norman OK
1250 PM CST Sat Dec 18 2021

Areas affected...Portions of far southeast TX and southwestern LA

Concerning...Severe potential...Watch unlikely 

Valid 181850Z - 182045Z

Probability of Watch Issuance...20 percent

SUMMARY...A line of storms will continue to move eastward this
afternoon. Isolated damaging winds should be the main threat. Watch
issuance is unlikely.

DISCUSSION...Convection has organized into line across parts of
coastal/far southeast TX early this afternoon. Some enhanced inbound
velocities associated with this line have recently been noted aloft
from the KLCH radar. With around 1000-1500 J/kg of MLCAPE and a
rich/moist low-level airmass present downstream across southwestern
LA, these storms should be able to maintain their intensity in the
presence of 30-40 kt of deep-layer shear. Occasional strong to
damaging winds appear to be the main threat with this activity in
the short term given the linear nature of the storms. However,
southwesterly flow in the 0-3 km layer is fairly weak, and generally
less than 25 kt per recent VWPs from KLCH/KPOE. This weakness in the
low-level wind field may tend to limit the overall severe threat
through the afternoon as these storms progress eastward. Therefore,
watch issuance appears unlikely at this time.

..Gleason/Kerr.. 12/18/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...LIX...LCH...

LAT...LON   30169438 30559399 31139381 31269262 30999176 30189168
            29729188 29489229 29569263 29739308 29649379 29539429
            30169438

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The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.